Database systems are typically used to effectively manage information that is organized for accessibility. To ensure availability, a system may include backup copies of the database in case the primary copy is damaged or lost. One common technique for database backup is to periodically copy an entire database onto computer-readable media. For example, an information system administrator may copy the database onto disks or tapes at the end of each week. Although a copy of the database can be preserved in this manner, copying the entire database is time-consuming and the activities between the backup intervals are lost if not tracked through other means.
Another technique of database backup involves maintaining copies of the same database on different computing machines. In the event that one of the databases became unusable, another copy of the database in another computing machine can still be accessed. This type of failover backup can ensure database availability. However, synchronizing multiple copies of the entire database in different machines in real-time is a complex and costly process.
An effective way to ensure the availability of a database without undue complexity or unnecessary loss of data continues to elude those skilled in the art.